Project Summary Decentering is a metacognitive process characterized by an open, objective, and psychologically-distant perspective on one?s own thoughts and emotions. It is a key component of many therapies for a range of emotional disorders, improving symptoms and increasing well-being. But the specific processes through which decentering imparts its benefits are not clear, and little is known about individual differences (i.e., symptom type, trait affect) and contextual features (i.e., state affect) that may impact the operation of decentering in daily life. The identification of such mechanisms and moderators of decentering would facilitate the long-term goal of improving therapeutic treatments of emotional disorders by creating more effective and individually-tailored interventions. The overall objective of this application is to demonstrate attentional and self-regulation mechanisms by which decentering exerts its impact in daily life across a full range of symptoms and affective experiences. The central hypothesis, informed by pilot data from the applicants? laboratories, is that decentering protects individuals from the negative consequences of extreme levels of negative and positive affect via its influence on specific attentional and self-regulatory processes. To test the hypothesis, two specific aims will be pursued: 1) demonstrate that broadened attentional focus and improved self-regulation mediate the association of decentering with daily symptoms and well-being; and 2) determine how decentering impacts the association of trait and state affect with symptoms and well-being in daily life, with the hypothesis that the association will be attenuated at high levels of decentering. These aims will be examined in a sample of 350 mixed clinical and non-clinical community-dwelling adults. Participants will complete a baseline assessment of relevant individual differences using mixed methods (self-report, clinical interview, eye-tracking for attentional bias, heart-rate variability for self-regulation). They will then complete a seven-day ecological momentary assessment study, with six random assessments each day, focused on self-reported current decentering, affect, symptoms, well-being, attentional processes, and self-regulation. This ecological momentary assessment design allows for the evaluation of dynamic within-person prospective processes that yield contextually-specific and potentially causal conclusions. This research is innovative, as it will provide new knowledge about for whom and when decentering is most effective, and it uses a novel methodological approach that includes multiple methods and externally-valid assessments. The proposed study is significant because it will lay the groundwork for refining and increasing the potency of decentering interventions, as well as identifying potential moderators that determine when and how decentering should be used to maximize positive therapeutic outcomes. Ultimately, this developmental research may remove critical barriers to improving the prevention and treatment of emotional disorders.